package thinkingInJava.generics;

//: net/mindview/util/Sets.java
import java.util.*;

public class Sets {
public static <T> Set<T> union(Set<T> a, Set<T> b) {
  Set<T> result = new HashSet<T>(a);
  result.addAll(b);
  return result;
}
public static <T>
Set<T> intersection(Set<T> a, Set<T> b) {
  Set<T> result = new HashSet<T>(a);
  result.retainAll(b);
  return result;
}	
// Subtract subset from superset:
public static <T> Set<T>
difference(Set<T> superset, Set<T> subset) {
  Set<T> result = new HashSet<T>(superset);
  result.removeAll(subset);
  return result;
}
// Reflexive--everything not in the intersection:
public static <T> Set<T> complement(Set<T> a, Set<T> b) {
  return difference(union(a, b), intersection(a, b));
}
} ///:~
